7D Auto ISO vs. fixed ISO?

Marshall, This was taken handheld AF on with single point used. My intent was to focus only on the Merganser but because of the distance was hoping to crop into a closer and better composition. This shot is not cropped. Filter was clean.

Thanks, RGF

The number one rule in birding is to shoot in good light (and with good reason). It simply becomes very difficult to get keepers in light as low as you were shooting in. You have a LOT going against you. I wouldn't take it too hard.

You'll have to fight detail-robbing Noise, lack of contrast, lack of detail due to the flat light, muted colors due to high ISO, added camera shake due to slow shutter speeds, subject motion blur, perhaps some lens softness from shooting wide open, the list goes on.

In addition, IME the 100-400 requires a good bit of contrast to focus well, and Does Not play well with filters (AF can be adversely affected).

So try taking the filter off, and wait for some nice light, and I guarantee you will be much happier!

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